What is the max free air heat transfer coefficient(film coefficient)?

In summary, at 1000 degrees C, the maximum free air heat transfer coefficient, also known as the film coefficient, is 5-25 W/m^2/K. However, when applied in thermal analysis with solid edge, the result may be a much higher number. This is because at such high temperatures, radiative heat transfer dominates over convective heat transfer. To accurately calculate the heat transfer rate, one should consider both convective and radiative heat transfer.
  • #1
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what is the max free air heat transfer coefficient(film coefficient)? at 1000 c?

i have a object that is at 1000 degree c by applying 900watt. i model it solid edge and apply heat generation load of 900 watt, from what i research air convection is 5-25 w/m^2/k. but when i apply that in the thermal analysis with solid edge. i get a massive number.

it only go back to 1000 degree c by applying convective file coefficient of like 400 w/m^2/k? why is that? is 400 w/m^2/k even possible?
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  • #2
At 1000 c, radiative heat transfer is going to dominate over convective. Try calculating the heat transfer rate from radiative heat transfer.
 

Related to What is the max free air heat transfer coefficient(film coefficient)?

1. What is the max free air heat transfer coefficient?

The maximum free air heat transfer coefficient, also known as the film coefficient, is a measure of the rate at which heat is transferred from a solid surface to the surrounding air. It represents the overall heat transfer resistance between the surface and the air and is typically measured in units of W/m2K.

2. How is the max free air heat transfer coefficient determined?

The film coefficient is determined through experiments or calculations using empirical correlations. It takes into account several factors such as the properties of the surface, air flow rate, and temperature difference between the surface and air.

3. What is the significance of the max free air heat transfer coefficient?

The film coefficient is an important parameter in heat transfer analysis and design of various heat exchange systems. It helps in predicting the heat transfer rate and determining the appropriate size and design of heat exchange equipment.

4. How does the max free air heat transfer coefficient vary with different surfaces?

The film coefficient is influenced by the nature and properties of the surface, such as its roughness, composition, and temperature. Different surfaces will have different film coefficients, which can significantly affect the overall heat transfer rate.

5. Can the max free air heat transfer coefficient be improved?

Yes, the film coefficient can be improved by increasing the surface area, increasing the air flow rate, or using materials with higher thermal conductivity. Various methods such as fins, turbulators, and surface coatings can also enhance the film coefficient and improve heat transfer efficiency.

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